Can Your Cholesterol Be Too Low?
Unlike a lot of men, the writer never worried about cholesterol -- until some surprising studies linked low cholesterol to violent behavior.
June 26, 2000 -- "This can't be right," the medical technician tells me, reading a number off the small display screen. "We'll have to do the test one more time."
"But wait," I object, telling her that my cholesterol level has always been on the low side. No use. Not once but twice, she jabs the tip of my finger and squeezes out a few drops of blood to test. The numbers remain stubbornly low: barely over 120. The average for most people is around 180.
As usual, I feel an absurd swell of pride at the results of the blood test, as if I've just passed an exam with flying colors. I've always counted myself lucky. Unlike a lot of men, I don't have to worry about cholesterol -- that notorious clogger of arteries.
Or so I thought. Then, a few months ago I read a headline that made me wonder: Low Cholesterol Linked to Violence, Suicide.
Violence? Suicide? Is it possible that someone's cholesterol level might be too low?
Smashing Cars and Other Things
To find out, I put in a call to Vivian Mitropoulou, PhD, who is studying the link between cholesterol levels and personality disorders at Mount Sinai School of Medicine in New York. The alarm sounded in the mid-1980s, she tells me, after researchers began testing the first drugs designed to lower elevated cholesterol levels. People taking these drugs seemed to be dying at an unusually high rate from causes unrelated to cardiovascular disease, she says.
Unrelated is right. As Mitropoulou says, "A lot of them seemed to be smashing their cars into bridges and doing all sorts of impulsive and violent things."
And there are other reasons to fret. At least a dozen reports show the risk of suicide may be substantially higher in people with low cholesterol. For instance, in a French study that tracked 6,393 men, published in the September 1996 issue of the British Medical Journal, those with low cholesterol were three times more likely than the other men to kill themselves. A study at Payne Whitney Clinic in New York, published in the March 1995 American Journal of Psychiatry, divided participants into four ranges of low to high cholesterol levels. Researchers found that the men with the rock-bottom cholesterol levels were twice as likely as those in the other three ranges to commit suicide.
They may also be more likely to hurt someone else. When Mitropoulou and her colleagues at Mount Sinai recently studied 42 patients with personality disorders, they found a strong link between lower-than-average cholesterol and impulsive, aggressive behavior.
What's behind the violent behavior and suicidal tendencies? One answer could be depression. In findings published in the September 1999 British Journal of Psychiatry, researchers from Finland's National Public Health Institute showed that in a group of more than 29,000 Finns studied, low total cholesterol put men at greater risk of being hospitalized for major depression. A link between low cholesterol and depression has turned up in at least half a dozen other studies.
The Serotonin Connection
No one knows for sure whether low cholesterol levels are the cause of these psychological problems -- or just an innocent bystander. It's always possible, for instance, that people who are depressed or violent eat less than psychologically healthy people, which could lower their total cholesterol level.
But one leading researcher, Beatrice Golomb, MD, PhD, an internist who specializes epidemiology, is convinced there is a direct link. I reached her at the University of California, San Diego, where she had reviewed all the existing studies on low cholesterol and violence for an article in the March 15, 1998 issue of the Annals of Internal Medicine.
The link, Golomb told me, may be the brain chemical serotonin. "We know that monkeys placed on low-fat or low-cholesterol diets show significantly lower serotonin activity in their brains. What's more, studies show that animals with low serotonin activity are more likely to be aggressive."
No one has looked to see whether low-fat or low-cholesterol diets decrease serotonin in humans. Golomb says there are good data from human studies linking low serotonin to both aggressive and violent behavior, including suicide. The connections between low serotonin, depression, and these behaviors are not yet understood. Antidepressant drugs like Prozac and other selective serotonin reuptake inhibitors, or SSRIs, are believed to work by increasing the effective concentration of serotonin in the brain.